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		<h1 id="0033-menus-viii---an-image-a-label-and-an-accelkey">0033: Menus VIII - An Image, a Label and an AccelKey</h1>

<p>Remember how I said that the <em>GTK</em> <code class="language-plaintext highlighter-rouge">ImageMenuItem</code> was deprecated? Well, with it went the easy way to add an accelerator key to a <code class="language-plaintext highlighter-rouge">MenuItem</code> that also has an image.</p>

<p>Well, whether it’s useful or not, we can fake it, so here goes nothing…</p>

<h2 id="fake-imagemenuitem-accel-key">Fake ImageMenuItem Accel Key</h2>

<div class="screenshot-frame">
	<div class="frame-header">
		Results of this example:
	</div>
	<div class="frame-screenshot">
		<figure>
			<img id="img0" src="../images/screenshots/012_menus/menu_17.png" alt="Current example output" />		<!-- img# -->
			
			<!-- Modal for screenshot -->
			<div id="modal0" class="modal">																	<!-- modal# -->
				<span class="close0">&times;</span>															<!-- close# -->
				<img class="modal-content" id="img00" />															<!-- img## -->
				<div id="caption"></div>
			</div>
			
			<script>
			// Get the modal
			var modal = document.getElementById("modal0");														// modal#
			
			// Get the image and insert it inside the modal - use its "alt" text as a caption
			var img = document.getElementById("img0");															// img#
			var modalImg = document.getElementById("img00");													// img##
			var captionText = document.getElementById("caption");

			img.onclick = function()
			{
			  modal.style.display = "block";
			  modalImg.src = this.src;
			  captionText.innerHTML = this.alt;
			}
			
			// Get the <span> element that closes the modal
			var span = document.getElementsByClassName("close0")[0];											// close#
			
			// When the user clicks on <span> (x), close the modal
			span.onclick = function()
			{ 
				modal.style.display = "none";
			}
			</script>
			<figcaption>
			Current example output
			</figcaption>
		</figure>
	</div>

	<div class="frame-terminal">
		<figure class="right">
			<img id="img1" src="../images/screenshots/012_menus/menu_17_term.png" alt="Current example terminal output" />		<!-- img#, filename -->

			<!-- Modal for terminal shot -->
			<div id="modal1" class="modal">																				<!-- modal# -->
				<span class="close1">&times;</span>																		<!-- close# -->
				<img class="modal-content" id="img11" />																		<!-- img## -->
				<div id="caption"></div>
			</div>
			
			<script>
			// Get the modal
			var modal = document.getElementById("modal1");																	// modal#
			
			// Get the image and insert it inside the modal - use its "alt" text as a caption
			var img = document.getElementById("img1");																		// img#
			var modalImg = document.getElementById("img11");																// img##
			var captionText = document.getElementById("caption");

			img.onclick = function()
			{
			  modal.style.display = "block";
			  modalImg.src = this.src;
			  captionText.innerHTML = this.alt;
			}
			
			// Get the <span> element that closes the modal
			var span = document.getElementsByClassName("close1")[0];														// close#
			
			// When the user clicks on <span> (x), close the modal
			span.onclick = function()
			{ 
				modal.style.display = "none";
			}
			</script>

			<figcaption>
				Current example terminal output (click for enlarged view)
			</figcaption>
		</figure>
	</div>

	<div class="frame-footer">																								<!-- ------------- filename (below) --------- -->
		The code file for this example is available <a href="https://github.com/rontarrant/gtkd_demos/blob/master/012_menus/menu_17_accel_fake_image_item.d" target="_blank">here</a>.
	</div>
</div>

<h2 id="dont-forget-to-add-accelgroup-to-your-window">Don’t Forget to Add AccelGroup to Your Window</h2>

<p>Because if you do forget, this isn’t gonna work. Here’s <code class="language-plaintext highlighter-rouge">TestRigWindow</code>’s constructor (we saw this last time, but here’s a refresher):</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">this</span><span class="p">()</span>
<span class="p">{</span>
	<span class="k">super</span><span class="p">(</span><span class="n">title</span><span class="p">);</span>
	<span class="n">setDefaultSize</span><span class="p">(</span><span class="mi">640</span><span class="p">,</span> <span class="mi">480</span><span class="p">);</span>
	<span class="n">addOnDestroy</span><span class="p">(&amp;</span><span class="n">quitApp</span><span class="p">);</span>

	<span class="n">accelGroup</span> <span class="p">=</span> <span class="k">new</span> <span class="n">AccelGroup</span><span class="p">();</span>
	<span class="n">addAccelGroup</span><span class="p">(</span><span class="n">accelGroup</span><span class="p">);</span>
		
	<span class="n">AppBox</span> <span class="n">appBox</span> <span class="p">=</span> <span class="k">new</span> <span class="n">AppBox</span><span class="p">(</span><span class="n">accelGroup</span><span class="p">);</span>
	<span class="n">add</span><span class="p">(</span><span class="n">appBox</span><span class="p">);</span>
		
	<span class="n">showAll</span><span class="p">();</span>
		
<span class="p">}</span> <span class="c1">// this()</span>
</code></pre></div></div>

<p>Such an important line:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">addAccelGroup</span><span class="p">(</span><span class="n">accelGroup</span><span class="p">);</span>
</code></pre></div></div>

<h3 id="add-the-filemenu">Add the FileMenu</h3>

<p>This really hasn’t changed since last time we did a fake image <code class="language-plaintext highlighter-rouge">MenuItem</code>:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="n">FileMenu</span> <span class="p">:</span> <span class="n">Menu</span>
<span class="p">{</span>
	<span class="n">FakeImageMenuItem</span> <span class="n">appleItem</span><span class="p">;</span>
	<span class="n">ExitMenuItem</span> <span class="n">exitMenuItem</span><span class="p">;</span>
	
	<span class="k">this</span><span class="p">(</span><span class="n">AccelGroup</span> <span class="n">accelGroup</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="k">super</span><span class="p">();</span>
		
		<span class="n">appleItem</span> <span class="p">=</span> <span class="k">new</span> <span class="n">FakeImageMenuItem</span><span class="p">(</span><span class="n">accelGroup</span><span class="p">);</span>
		<span class="n">append</span><span class="p">(</span><span class="n">appleItem</span><span class="p">);</span>
		
		<span class="n">exitMenuItem</span> <span class="p">=</span> <span class="k">new</span> <span class="n">ExitMenuItem</span><span class="p">(</span><span class="n">accelGroup</span><span class="p">);</span>
		<span class="n">append</span><span class="p">(</span><span class="n">exitMenuItem</span><span class="p">);</span>

	<span class="p">}</span> <span class="c1">// this()</span>
	
	
<span class="p">}</span> <span class="c1">// class FileMenu</span>
</code></pre></div></div>

<h3 id="the-all-new-fakeimagemenuitem">The All-new FakeImageMenuItem</h3>

<p>This is the mouthful of code you’ll need to chew on to get this working:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="n">FakeImageMenuItem</span> <span class="p">:</span> <span class="n">MenuItem</span>
<span class="p">{</span>
	<span class="nb">string</span> <span class="n">actionMessage</span> <span class="p">=</span> <span class="s">"You have added one (1) apple to your cart."</span><span class="p">;</span>
	<span class="n">Box</span> <span class="n">imageMenuBox</span><span class="p">;</span>
	<span class="nb">string</span> <span class="n">labelText</span> <span class="p">=</span> <span class="s">"Buy an Apple"</span><span class="p">;</span>
	<span class="nb">string</span> <span class="n">imageFilename</span> <span class="p">=</span> <span class="s">"images/apples.jpg"</span><span class="p">;</span>
	<span class="n">Image</span> <span class="n">image</span><span class="p">;</span>
	<span class="n">AccelLabel</span> <span class="n">accelLabel</span><span class="p">;</span>
	<span class="kt">char</span> <span class="n">accelKey</span> <span class="p">=</span> <span class="sc">'a'</span><span class="p">;</span>
   
	<span class="k">this</span><span class="p">(</span><span class="n">AccelGroup</span> <span class="n">accelGroup</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="k">super</span><span class="p">();</span>
		<span class="n">addOnActivate</span><span class="p">(&amp;</span><span class="n">reportStuff</span><span class="p">);</span>
				
		<span class="n">imageMenuBox</span> <span class="p">=</span> <span class="k">new</span> <span class="n">Box</span><span class="p">(</span><span class="n">Orientation</span><span class="p">.</span><span class="n">HORIZONTAL</span><span class="p">,</span> <span class="mi">0</span><span class="p">);</span>
		<span class="n">add</span><span class="p">(</span><span class="n">imageMenuBox</span><span class="p">);</span>

		<span class="n">image</span> <span class="p">=</span> <span class="k">new</span> <span class="n">Image</span><span class="p">(</span><span class="n">imageFilename</span><span class="p">);</span>

		<span class="n">accelLabel</span> <span class="p">=</span> <span class="k">new</span> <span class="n">AccelLabel</span><span class="p">(</span><span class="n">labelText</span><span class="p">);</span>
		<span class="n">accelLabel</span><span class="p">.</span><span class="n">setXalign</span><span class="p">(</span><span class="mf">0.0</span><span class="p">);</span>
		<span class="n">accelLabel</span><span class="p">.</span><span class="n">setAccelWidget</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
		
		<span class="n">addAccelerator</span><span class="p">(</span><span class="s">"activate"</span><span class="p">,</span> <span class="n">accelGroup</span><span class="p">,</span> <span class="n">accelKey</span><span class="p">,</span> <span class="n">ModifierType</span><span class="p">.</span><span class="n">CONTROL_MASK</span><span class="p">,</span> <span class="n">AccelFlags</span><span class="p">.</span><span class="n">VISIBLE</span><span class="p">);</span>

		<span class="n">imageMenuBox</span><span class="p">.</span><span class="n">add</span><span class="p">(</span><span class="n">image</span><span class="p">);</span>
		<span class="n">imageMenuBox</span><span class="p">.</span><span class="n">packEnd</span><span class="p">(</span><span class="n">accelLabel</span><span class="p">,</span> <span class="kc">true</span><span class="p">,</span> <span class="kc">true</span><span class="p">,</span> <span class="mi">0</span><span class="p">);</span>
	
	<span class="p">}</span> <span class="c1">// this()</span>
	
	
	<span class="kt">void</span> <span class="n">reportStuff</span><span class="p">(</span><span class="n">MenuItem</span> <span class="n">mi</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="n">writeln</span><span class="p">(</span><span class="n">actionMessage</span><span class="p">);</span>
		
	<span class="p">}</span> <span class="c1">// exit()</span>
	
<span class="p">}</span> <span class="c1">// class FakeImageMenuItem</span>
</code></pre></div></div>

<p>There’s a lot going on here, but skipping over the bits we’ve covered in earlier posts, here’s what’s new or unusual:</p>

<p>First is this line:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">addOnActivate</span><span class="p">(&amp;</span><span class="n">reportStuff</span><span class="p">);</span>
</code></pre></div></div>

<p>I bring this to your attention because in the previous example of accelerator keys, we didn’t use this line. But this time, we do and we’ll see why in a moment.</p>

<p>After that we:</p>

<ul>
  <li>create the <code class="language-plaintext highlighter-rouge">Box</code>,</li>
  <li>stuff the <code class="language-plaintext highlighter-rouge">Box</code> into the <code class="language-plaintext highlighter-rouge">MenuItem</code> (which is a container, right?),</li>
  <li>we build an <code class="language-plaintext highlighter-rouge">Image</code>,</li>
  <li>and a <code class="language-plaintext highlighter-rouge">Label</code>…</li>
</ul>

<p><em>Not</em> a <code class="language-plaintext highlighter-rouge">Label</code>, an <code class="language-plaintext highlighter-rouge">AccelLabel</code>. And why? Because we have to do these extra bits of twiddling to get this to work:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">accelLabel</span><span class="p">.</span><span class="n">setXalign</span><span class="p">(</span><span class="mf">0.0</span><span class="p">);</span>
<span class="n">accelLabel</span><span class="p">.</span><span class="n">setAccelWidget</span><span class="p">(</span><span class="k">this</span><span class="p">);</span>
</code></pre></div></div>

<p>And those functions are only available with the <code class="language-plaintext highlighter-rouge">AccelLabel</code>.</p>

<p>The <code class="language-plaintext highlighter-rouge">Xalign()</code> call gives us room in the <code class="language-plaintext highlighter-rouge">Box</code> so the accelerator key (that’s <strong>Ctrl-A</strong>) won’t overlap the <code class="language-plaintext highlighter-rouge">Label</code>.</p>

<p>And then the <code class="language-plaintext highlighter-rouge">AccelLabel</code> needs to know which <code class="language-plaintext highlighter-rouge">Widget</code> to pair up with. In this case, it’s the <code class="language-plaintext highlighter-rouge">FakeImageMenuItem</code> (which is really a <code class="language-plaintext highlighter-rouge">MenuItem</code>).</p>

<p>Now with this line, we get to the other half of why we still need to hook up the signal:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">addAccelerator</span><span class="p">(</span><span class="s">"activate"</span><span class="p">,</span> <span class="n">accelGroup</span><span class="p">,</span> <span class="n">accelKey</span><span class="p">,</span> <span class="n">ModifierType</span><span class="p">.</span><span class="n">CONTROL_MASK</span><span class="p">,</span> <span class="n">AccelFlags</span><span class="p">.</span><span class="n">VISIBLE</span><span class="p">);</span>
</code></pre></div></div>

<p>When we added accelerators in the previous example, last post (which I’ve also done in this example with the <code class="language-plaintext highlighter-rouge">Exit</code> <code class="language-plaintext highlighter-rouge">MenuItem</code> so you have both close to hand for comparison) we did it via an overloaded call to the super-class constructor.</p>

<p>But here, we can’t because the work is split up between several widgets. So we use the <code class="language-plaintext highlighter-rouge">addAccelerator()</code> function instead.</p>

<p>Now another crucial thing to bear in mind: When you pack the <code class="language-plaintext highlighter-rouge">Image</code> and the <code class="language-plaintext highlighter-rouge">AccelLabel</code> into the <code class="language-plaintext highlighter-rouge">Box</code>, you have to <code class="language-plaintext highlighter-rouge">add()</code> the image and <code class="language-plaintext highlighter-rouge">packEnd()</code> the <code class="language-plaintext highlighter-rouge">AccelLabel</code>, which is these lines:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="n">imageMenuBox</span><span class="p">.</span><span class="n">add</span><span class="p">(</span><span class="n">image</span><span class="p">);</span>
<span class="n">imageMenuBox</span><span class="p">.</span><span class="n">packEnd</span><span class="p">(</span><span class="n">accelLabel</span><span class="p">,</span> <span class="kc">true</span><span class="p">,</span> <span class="kc">true</span><span class="p">,</span> <span class="mi">0</span><span class="p">);</span>
</code></pre></div></div>

<h2 id="conclusion">Conclusion</h2>

<p>I’m going to come clean, here. I didn’t come up with the idea for this code. The <em>C</em> version appears in a comment in the <em>GTK</em> source. I did, however, port it to <em>D</em> which turned out to be more of a challenge than I thought it would be. But when it finally worked, the feeling of satisfaction was worth all the griping and hair-pulling. (Isn’t it always?)</p>

<p>And that just about sums up today’s exploration of accelerator keys and imagery on menus. Be kind to each other and next time we’ll talk about a little <em>D</em>-centric OOP trick we can use so we don’t have to pass the <code class="language-plaintext highlighter-rouge">AccelGroup</code> down from the <code class="language-plaintext highlighter-rouge">Window</code> object through all those levels to get it to where it’s needed in the <code class="language-plaintext highlighter-rouge">MenuItem</code> objects.</p>

<p>Until then…</p>

<div class="blog-nav">
	<div style="float: left;">
		<a href="./0032-accelerator-keys.html">Previous: Accelerator Keys</a>
	</div>
	<div style="float: right;">
		<a href="./0034-accelgroup-singleton.html">Next: AccelGroup Singleton</a>
	</div>
</div>
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